1. Field of the Invention
The present invention relates to a container produced from a single-layered, helically bent sheet metal strip, in the upper or in the lower border region of the sheet metal strip a first helically running border portion of the sheet metal strip being bent out via a helically running outwardly bent edge with a curved region toward the outside of the container as a protruding flange, there being a second helically running border portion in the lower/upper border region of the sheet metal strip, and the helically running border regions of the sheet metal strip, which each border one another in a manner adjacent in terms of height, being connected to one another in a fluid-tight manner via a continuous, helically running welded joint.
2. Prior Art
Containers produced from helically bent sheet metal strip are known from DE 2 250 239 A or EP 1 181 115 B1. In order to produce containers, a coil with a diameter corresponding to the container diameter is shaped here from a sheet metal strip. During the production of a container of this type, the mutually assigned coil sheet metal strip borders are first of all bent out and are subsequently connected to one another in a fluid-tight manner on the outside of the container by means of a seam. For this purpose, the mutually opposite longitudinal edges of the sheet metal strip are each bent out in a U-shaped manner and the mutually assigned sheet metal borders bent out in a U-shaped manner are placed one inside another and are subsequently connected by seaming. This system is commercially known as the Lipp dual-seam system and has proven successful in diverse situations. By means of said Lipp dual-seam system, simple and rapid production of the containers with a variable diameter and variable height is possible. Transportable sheet metal bending and installation apparatuses ensure that the container can be installed at the respective erection site and the transport volume can be corresponding reduced.
It is known from DE 199 39 180 A1 to produce a container in such a manner that a first border portion is bent out toward the outside, forming a helically running outwardly bent edge, and a second border portion of the sheet metal strip, which is arranged adjacently thereabove, is bent over outward and is then connected to a first border portion by a seam.
For the previous applications of said container system, for example for storing bulk materials from agriculture and forestry, or biowaste, the containers have excellent stability, tightness and media resistance. However, for further applications, such as, for example, the storage of fluid media, such as vegetable oils, natural oil or the like, a significantly larger container volume is required, and in which applications the tightness has to be reliably ensured. The associated increased mechanical stability of the containers cannot be adequately ensured by the known seam systems. In particular, the seam system reaches its limits in the event of great sheet metal thicknesses.
In order to provide containers which are produced helically from bent sheet metal strip and the range of application of which is increased, in particular with regard to the realization of a large storage volume and/or increased mechanical stability while ensuring nevertheless simple and rapid production capability and installation, solutions have been developed which replace the seam connection with a welded joint.
WO 2014/048515 A1 discloses a container produced from a helically bent sheet metal strip of the type described at the beginning, wherein the border portions of the adjacent border regions, which run one above another in terms of height, of the sheet metal strip are connected to one another via a welded joint. The border regions overlap here and are connected to one another in a fluid-tight manner by means of two separate weld seams. The distance present between the weld seams gives rise, in the overlapping region of adjacent border regions of the sheet metal strip, to a gap region between the overlapping walls, which gap region is not controllable in a simple manner with respect to possible risks of corrosion or the like after the container has been produced.